Synthesis and ex-situ evaluation of quaternized polysulfone as an anion exchange ionomer for AEM technologies

Anion exchange ionomer (AEI) is a critical component used on anion exchange membrane fuel cell (AEMFC) and alkaline water electrolyzer (AWE). In this work, quaternized polysulfone with different functionalization degree were used as an ionomer to evaluate the performance in the oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR), both implied in the operation of AEMFC and AWE. The synthesized ionomer exhibited a better performance in both reactions in comparison to the commercial AEI Aemion (R). PSf-130 exhibited better performance, since IEC and surface area increases twice regarding the same parameters in the PSf-60. The PSf-130 conductivity increases three times regarding the value exhibited by PSf-60. Finally, the J(lim) and J(k) increases 67% and 100% for ORR. On the other hand, the same catalytic parameter increased 44% and 35% for HOR comparing both polysulfone-based ionomers. The Tafel slope values do not showed drastically changes for different ionomers indicating the same rate determining step (RDS) and the same mechanism in both reactions for all the ionomers.

Automated summary

This study evaluated the performance of different functionalized quaternized polysulfone ionomers in the oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) in anion exchange membrane fuel cells (AEMFC) and alkaline water electrolyzers (AWE). The synthesized ionomers outperformed the commercial AEI Aemion, with the PSf-130 showing the best performance. Compared to the PSf-60, the PSf-130 had twice the ion exchange capacity and surface area, and three times the conductivity. The ORR and HOR current density increased by 67% and 100% respectively for the PSf-130, while the same catalytic parameters increased by 44% and 35% for the PSf-60. The Tafel slope values did not show significant changes for different ionomers, indicating the same rate determining step (RDS) and mechanism in both reactions for all ionomers.